Diabetes is reaching epidemic proportions, with a worldwide prevalence of 150 million currently, and is predicted to increase to 300 million by 2025. Renal disease in patients with type 2 diabetes is the leading cause of terminal renal failure and a major health care problem. Oxidative stress is a well established contributor to the pathophysiology of diabetes and its complications. There is a need to elucidate the mechanisms by which increased oxidative stress accelerates the development of diabetic complications, in order to expand prevention and treatment options. There is also a need to explore gender differences in the progression of type 2 diabetes, its complications, and the response to therapy. Alterations in the expression of the isoforms of nitric oxide synthase (NOS) may contribute to the pathophysiology of diabetic nephropathy through alterations in levels of nitric oxide (NO), which can lead to the formation of peroxynitrites. These in turn promote the formation of potent reactive oxygen and nitrogen species, which leads to mitochondrial dysfunction and cell death. Therefore, an optimal combination of antioxidant nutrients to alleviate the burden of oxidative stress in diabetic patients would be beneficial. The obese Zucker (fa/fa) rat is a good model for type 2 diabetes associated with obesity. Using this model we will test the following hypotheses: (1) progression of diabetes and progression of nephropathy in type 2 diabetes will be accompanied by changes in nitric oxide synthases with increases in neuronal NOS (nNOS) and inducible NOS (iNOS) and decreases in endothelial or constitutive NOS (cNOS); (2) antioxidants will attenuate the changes in renal function, in part through an effect on the expression of NOS isoforms. This investigation will be accomplished by the following specific aims: (1) monitor the expression of nitric oxide synthases, cNOS, iNOS and nNOS, during the progression of renal dysfunction in the Zucker rat model of type 2 diabetes, and correlate these findings with renal function, including glomerular filtration rate (GFR) and urine albumin, in both males and females; (2) examine the effect of administering an antioxidant fortified diet on renal function and the expression of nitric oxide synthases in diabetic male and female Zucker rats, and determine if there is a gender related response to therapy. The ultimate goal of these studies is to establish better therapies that may include antioxidant therapy, to prevent the long term complications of diabetes, including nephropathy. [unreadable] [unreadable]